The Deluge Lake trail is a great day hike in the Gore Range. The trailhead is in East Vail at the end of the frontage road, right at the base of Vail Pass. It's about 4 miles and 3000 feet of vertical up, but there aren't many steep sections. The trail is narrow in places, but overall it's in good shape. We did the hike on July 10, 2013 and there was still some snow around the lake at the top. If afternoon showers are in the forecast, be sure and start early as you don't want to be caught on top of the mountain in a lightning storm. Bring plenty of water as you'll probably be on the trail for 5 - 6 hours. It took us (2 guys, 52 & 71 in decent shape) about 2.75 hours each way.
Here's a link to a very good description of the hike.